Such a device is known from DE 102 36 402 A1.
Devices of this type are used for measuring an internal or an external diameter of a workpiece for example. Here, a test fluid is supplied to a flow channel. The test fluid flows through the flow channel in the direction of flow of the test fluid. The test fluid is subjected to a first test fluid pressure, whereafter it flows through a reference nozzle arranged in the flow channel and is then supplied to a measurement nozzle which is connected in fluidic manner to the flow channel. The test fluid flows out from the measurement nozzle into a gap between the measurement nozzle and the workpiece being measured which serves as a flow restrictor. The magnitude of the gap, which is dependent on the geometry of the workpiece, affects the throttling effect produced by the gap and thus has an effect on the second pressure of the test fluid present between the reference nozzle and the measurement nozzle downstream of the reference nozzle. In this way, the geometry of the workpiece can be determined from a measurement of the first pressure of the test fluid and the second pressure of the test fluid.
When there are a large number of workpieces, in the case of parts of injection pumps or machine tools for example, it is necessary for the dimensions of the workpieces to be produced to the finest of tolerances and to check as to whether these workpiece dimensions are being maintained.
Based on this background, it would be desirable to provide a device of the type mentioned hereinabove which will enable particularly precise geometrical measurements to be made. Moreover, it would be desirable to provide a method for measuring the geometry of a workpiece which is particularly precise.